Field of the Invention
The present invention relates to a numerical controller configured for operation based on tabular data, and more particularly, to a numerical controller having a function of specifying a reference value for control to achieve a target state based on tabular data.
Description of the Related Art
A path table operation function is generally known as a method of drivingly controlling control axes in synchronism with one another and with the movement of a reference axis. In this method, position information on the control axes corresponding to the position of the reference axis is previously stored in tabular data in a memory or the like. Based on the information stored in the tabular data, the control axes are operated in synchronism with the reference axis. According to this function, the tabular data (path table program), in which a time, axis position, spindle position, or auxiliary function, such as an M code, are set, are stored in advance in the memory or a network-connected storage device and are sequentially read as the axes are driven.
Japanese Patent Applications Laid-Open No. 59-177604 and No. 2003-303005 disclose numerical controllers based on the so-called path table operation function or electronic cam control. Thus, a tool operation independent of a machining program can be freely performed, so that a reduction in machining time and improvement in machining accuracy can be achieved.
A time, axis position, or spindle position that serves as a reference (hereinafter referred to as “reference value”) and a command for controlling an axis, spindle, or auxiliary function corresponding to the reference value are described in conventional tabular data. The operation for the command for controlling the state of the axis, spindle, or auxiliary function is started when the reference value is achieved. For a command for controlling the rotational speed of the spindle, for example, acceleration or deceleration for a specified rotational speed is started when the described reference value is achieved. For a spindle indexing command, on the other hand, spindle indexing is started when the reference value is achieved.
A certain operating time is required to achieve the specified rotational speed after the start of the acceleration or deceleration of the spindle and to complete the indexing after the start of the spindle indexing operation. For the command for controlling the state of the axis, spindle, or auxiliary function, it is necessary to take account of an operating time to achieve a target state based on a reference value for the execution of an operation start command. Thus, the reference value for the start of the operation is determined by previously obtaining the operating time by calculation or measurement for each command.
However, the operating time to achieve the target state for each command for controlling the state of the axis, spindle, or auxiliary function varies depending on the machine configuration of a machine tool and parameter setting. In this case, the operating time may be the time for the spindle to achieve the specified rotational speed or the time to complete the spindle indexing. In some cases, therefore, differences in power consumption and operating time may be caused, depending on the machine configuration of the machine tool and parameter setting, despite the use of the same tabular data for operation. Consequently, in the case of the command for controlling the state of the axis, spindle, or auxiliary function, it is necessary to calculate the operating time to achieve the target state after the start of the operation and create optimal tabular data for the machine configuration of each machine tool and for each parameter setting. Possibly, therefore, the work may be complicated.